Hoisting machinery for operating grab-buckets.



' A. SMITH. HOISTlNG MACHINERY FOR OPERATING GRAB BUCKETS.

APPLICATION FILED MAY 4. I912.

1mm. Patented Feb; 1, 1m

3 SHEETS-SHEET 1.

Iii/a ATTOR/VE Y5 1,170,463, I Patented Feb. 1, 1916.

A: SMITH. I HOlSTING MACHINERY FOR OPERATING GRAB BUCKETS.-

APPLICATION FILED MAY4| 1912.

3 SHEETS-SHEET 2.

- BY W %Z% Mnrronmrs VA. SMITH. I HOISTING MACHINERY FOR OPERATING GRABBUCKETS.

APPUCATION FILED MAY 4, 1912.

L10A63, Patented Feb. 1, 1916.

3 SHEETSSHEET -3- W/TNESSES lNl/EIi/TOR are ears an no.

AUGUSTUS SMITH, oE onrn PLAINEIELnMW JERSEY, ASSIGNOR T0 BERGEN rom'rmun woaxs, 0E BAYonnE, NEW JERSEY, a coar'onarron or new JERSEY.

HOISTING- MACHINERY-FOR OPERATING GRAB-BUCKETS.

Specification of Letters Patent.

Patented Feb. 1, 1916.

Application filed May 4, 1912. Serial No. 695,079.

To all whom it may concern 'Be it known that l, AUGUSTU SMITH, a citizenof the United States of America, and residing at North Plainfield, inthe. county of Somerset and State of New Jersey, have invented a certainnew and useful Improvement in Hoisting Machinery for OperatingGrab-Buckets, of which the following is a specification.

Grab shovels or buckets for digging coal, ore or similar materials areusually operated by two ropes or chains, one attached to the frame ofthe bucket hereinafter referred to as the holding rope which hoists andlowers the whole bucket and the other rope hereinafter, called theclosing rope attached to some gear within the bucket for drawing thejaws together to make it dig into the matter that is handled. Theseropes are generally wound each on a separate drum actuated through somefrictional device from a power shaft driven either by belt, steam engineor electric motor. Levers in the hands of the operator suitablyconnected to the friction clutches in the hoisting machine give theoperator extreme delicacy of control of the movements of the bucket, hebeing thus able to hoist or lower the bucket or to open and close it atwill. The horizontal movement of the bucket is often controlled by atrolley which is sometimes moved by a separate engine or motoror'sometimes by a device such as the differential drum described inMcIntyre Patent No. 1,004,451 connected by gearing to the holding drumof the hoisting mechanism. The apparatus for moving the buckethorizontally has nothing to do with my present invention, and for thepurpose of simplicity, I have omitted the ropes leading from the.difierential drum, which I prefer to use, to the trolley and likewiseall suggestion of an independent control of the trolley by aseparate'engine.

A grab bucket for hoisting coalusually weighs about twice as much as thecoal it can hold, and therefore the hoisting engine has to be powerfulenough to lift about three times the net weight of the coal which powercould be saved if a counterweight could be made use of. The greatdifliculty in using a counterweight, however, has been that the diggingpower of the bucket into the coal or ore is a function of its weight,and-if the counterweight acted so as to make the bucket rest lightly onthe materialto be excavated,

the bucket would have no digging power and could not fill itself.Another difiiculty that has heretofore been encountered in mechanisms ofthis character is in the lowering of the empty bucket. Friction clutchesor brakes, or both, are commonly used for this purpose which waste agreat deal of power and give trouble by heating; motors are sometimesused to absorb the energy of the falling bucket by creating negativeelectrical energy, and reversing steam engines are sometimes used in asimilar way. All of these methods involve numerous mechanical orelectrical difliculties and are objectionable for one reason or another.I

One object of my invention is to introduce a counterweight in such a waythat the full weight of the bucket will rest on the material to beexcavated but so that the counterweight will come into play when thebucket is to be hoisted, the present arrangement be-,

ing such that the counterweight is lifted when the bucket is lowered,thus avoiding all the difficulties involved by the methods abovementioned. Another object of my invention is to eliminate the frictionclutches between the winding drums and the driving shaft so that thenumber of levers to be manipulated by the operator will be therebyreduced, while at the same time the cost and weight of the hoistingmechanism is thereby reduced. I

In the accompanying drawings, Figure 1 is a diagrammatic representationof a clam shell grab bucket with hoisting and closing ropes wound onseparate drums, and a differential drum geared to the holding drum forcontrolling the horizontal position of the trolley, the connection towhich is omitted for the sake of clarity; Fig. 2 is a plan of the drumarrangement; and Figs. 3 and 4 are plans of modified drum arrangements.

Referring to the drawings in greater detail, Fig. 1 is a diagrammaticrepresentation of a clam shell grab bucket with its hoisting and closingropes 11 and 12 respectively wound on separate drums 13 and 14, drivenindependently by the power shafts 15. The difierential drum 16, gearedto the holding drum 13, controls the horizontal position of the trolley,(not shown), the connection between the two being omitted for clearness.A counterweight 17 to offset the empty bucket is shown attached to theholding drum 13. Fig. 2 is a plan view of this hoisting mechanism drawnto a larger scale. .An electric motor 18 (which may obviously besubstituted by a reversible steam engine) is shown directly connected byspur gearing 19 to the holding drum 13 and. a similar motor 20 (orreversible steam engine) is shown directly connected by spur gearing 21to the closing drum 14. The differential drum 16 is geared at 22 to theholding drum in 13. A friction clutch 23 is introduced for locking thetwo motor shafts together'at the will of the operator when it may bedesirable to have the drums 13 and 14 revolve together, as in hoistingafter the bucket is {6 closed, or Inore particularly in lowering theempty bucket. If this clutch were omitted, one mOtor or steam enginemight tend to drive its drum faster than the other and thus cause thebucket to open or close or .0 one of the operating ropes to becomeslack. .In the machine shown in Fig. 2, the closing motor 20 has to belarge enough to close the [bucket alone by means of the drum 14 whichrequires considerably more power than is 85 necessary subsequently tolift the bucket when the holding motor is assisting.

Fig. 3 is a plan view of another arrangement drawn to'a somewhatlargerscale. In

this case the motor 24 which drives the hold- U ing drum 25 also drivesthe differential drum D, and the main spur wheel 26, which is rigidlyconnected to the bevel wheel 27 of i an equalizing gear mechanism. Themotor 28 drives a gear 29 which is keyed to the i5 shaft 30 of theclosing drum 31 and turns with it the bevel gear 32 whichis keyed to thesame shaft. Engaging between the gears 27 and 32 are intermedlate bevelgears 33, 34, of the planetary type carried by a 0 face plate 35 boltedto the closing drum 31, .the mechanism being such that when the motor orengine 28 revolves the shaft 30 the closing drum 31' will revolve atless speed .but with greater pulling power. In the arrangement of gearsshown, the closin drum 31 will revolve at one half the spe d and withtwice the pulling power it would if the r motor 28 drove it directly asin the case shown in Fig. 2 providing always that the abutment gear 27isheld stationary by the gear 26 which is locked to the holding drum.Instead of the bevel gears shown in this figure for the sake of clearlyillustrating the relative motion of the closing drum and its shaft,gears of any planetary type could be used and-any desired ratio obtainedin the relative rotations and torques of shaft 30 and drum 31. In thiscase a friction clutch can be introduced at 36 looking the closing .9drum 31 to the gear wheels 29 by means of the friction surface 37, whichby reason of the train of gears shown will lock drums 25 and 31 togetherwith the same effect and for the same purpose as the friction clutch 23l shown in Fig. 2.

In both of the arrangements illustrated i in Figs. 2 and 3 it isnecessary for the holding motor 18 or 24 to be started immediately afterthe bucket is closed so that it may assist the closing motor to lift thebucket as well as to prevent the holding rope from becoming slack andentangled in the bucket for the reason that the continued rotation ofthe closing motor begins to lift the bucket the instant after the jawsmeet. When -motors or steam engines of large size are used andespecially in the case of motors, it

1s impossible to accelerate the holding motor by the fact that when thebucket is burying itself in the material to be excavated, the frame ofthe bucket to which the holding rope is attached actually sinks so thatrope has to be paid out by the holding drum-if the bucket is to get itsfull load which means that the holding motor hasto revolve in thedirection to lower the bucket, while the closing motor is revolving inthe direction to close the bucket, which is the same direction ofrotation that is required to lift it. Hence a if the holding motor orengine be directly geared to the holding drum, asshown in Figs. 2 and'3,it must actually be reversed and then brought to speed to catch up Withthe closing motor. In the case of large motors or engines this is verydiflicult if not impossible to accomplish and hence the common use ofthe friction clutch by means of which the holding drum can be startedwith less inertia and the closing drum checked a little if necessaryuntil the holding drum can take its share of the lift. Fig. 4 shows thearrangement I have-invented for'overcoming this difficultynotwithstanding the size and inertia of the motors or engines.

The reversible motor 38 or steam engine is geared by means of the gearwheels 39 and 40 to the shaft 41 on which is keyed a counterweight drum42 and a ratchet wheel 43. The holding drum 44 on which the holding ropeis wound is not keyed to the shaft 41,

but is loosely mounted on it, and arranged to be revolved by pawls 45engaging the ratchet wheel 43 so that when lifting the bucket the pawlswill engage the ratchet wheel and cause drum 44 to revolve with it butso that the pawls will travel freely over the ratchet if the holdingdrum 44 should tend to turn in the hoisting direction under some otherforce. f

The differential drum 46 which I prefer to use for regulating thehorizontal posi tion of the bucket is drum 44 so as to revolve with itin some,

geared to the holding fixed ratio as by means of spur gears 47 and 48,47 being bolted to the holding drum 44. The closing drum 49 is looselymounted on the shaft 41 and driven by planetary gears similar to thoseshown in Fig. 3. In this case the abutment bevel gear 50 is keyed to theshaft 41 and is held stationary by the holding motor 38 when the latterdoes not revolve. The bevel gear 51 is bolted to the spur wheel 52,driven by the spur pinion 53 on the closing motor or engine shaft 54.Planetary gears 55 and 56 carried by a disk 57 bolted to the closingdrum are meshed with gears 50 and 51 so that when the abutment gear 50is held stationary and the driving gear 51 turned by the motor 54, theplanetary disk between them and the closing drum with it will revolve atone half the speed of 51 and with twice the pulling power. As in Fig. 3any other system of planetary gears could be substituted for the bevelgears to accomplish the same result.

Friction of the necessary amount is intro duced between the holding drum44 and closing drum 49, as for instance by friction surfaces 58 turnedin the adjacent flanges of the drums and a coil spring 59 acting toforce drum 44 against drum 49 so that when drum 49 revolves, drum 44will be subjected to a drag tending to make it revolve simultaneously.Now when the closing drum 49 is revolved by motor or engine 54 causingthe bucket to close and dig into the material to be excavated, theholding drum 44 will tend to turn with it sufliciently to keep theholding rope always tight but not with sufficient force to materiallylift the bucket. As

above mentioned, the holding. drum 44 is free to revolve in thisdirection, its driving pawls slippin over the ratchet wheel 43 which isstan ing still or, it may be, even backing down in case it should benecessary to reverse the holding motor 38 so as to give out sufficientslack rope to permit the bucket to sink into the material as the jawsare closed by the closing drum.

As soon as the jaws of the bucket meet,

the continued revolution of the closing drum will commence to lift thebucket and will drag with it the holding drum 44 keeping the holdingrope always taut, the pawls slipping as fast as necessary over theratchet wheel 43. When the bucket has been closed, however, the holdingmotor 38 will be reversed if it has been backing down or would bestarted, if at rest, in the direction to hoist the bucket and would bebrought up to speed as rapidly as it can be accelerated. The speed ofrotation of the closing drum 49 which was half that of the gear wheel 51-when the motor 38 was at rest will gradually be accelerated as gearwheel 50 is accelerated by motor 38. Notwithstanding .thereafter motor38 be excavated with the the bucket, motor 54 this, motor 38 willrapidly overtake motor.

54 in speed until the ratchet wheel 43 revolves as fast as the holdingdrum 44 when the ratchet wheel will pick up the pawls and and thecounterweight on drum 42, if one be used, will assist motor 54 inlifting the loaded bucket. As soon as 5 motor 38 drives the shaft 41,and the bevel gear 50 keyed to it, at the same angular velocity, asbevel gear 51 is driven, the relative motion in the planetary gears willcease and both motors and the counterweight, if there be one, willloaded bucket. The counterweight may be made to balance the empty bucketand all of the friction of the machine, if necessary, so that the motorswill be called on to lift only the net Weight of the material to behoisted. The motor 54 will be of suflicient size to cause the bucket todig into the material to assistance only that is afforded by theplanetary gears. To open can be checked or stopped and the continuedwinding in on the holding line by motor 38 will transfer the weight ofthe bucket to the holding drum 44 causing the bucket to open, or if theholding drum 44 be stopped, opened by reversing the direction ofrotation of motor 54 and the closing drum. When the bucket has beenopened both m0- tors must be reversed together to return the emptybucket down to the material to be excavated. In returning the emptybucket, its weight will be mostly carried by the holding drum 44, thepawls coming into play on the ratchet wheel to resist the weight of thebucket. In lowering the bucket, motor 38 will have to lift thecounterweight by means of the counterweight drum 42 and if thecounterweight be large enough to over-balance the bucket to the extentof the friction of the machinery, motor 54 will evidently have toovercome, on the return of the bucket, this surplus weight of thecounterweight as well as the friction of the machine when returning.Motor 54 in act together to lift the the bucket can be.

llt

returning the bucket will have to overcome only the friction of turningits own drum and gears so that there will be difliculty in compellmg thetwo motors to run at exactly the same speed. This difliculty will be Iallowlng the bucket to open or close or one rope to become slack,additional friction may be applied by the thrust collar 60 workingthrough the ratchet wheel by thrust pins on the coil spring 59 toproduce any required friction at the" surface 58, this device beingequivalent to. the friction clutchesplication of my invention in whichmotors or steam engines are employed directly geared to the holding andclosing drums of a hoisting machine with a counterweight on the holdingdrum, or geared to it, opposed to the-weight of the bucket. I propose tooperate the closing and holding ropes of the hoisting machineindependently by reversible motors or steam engines or other drivingpower and to counterweight the holding drum so that the weight of theempty bucket may be offset in lifting and so that the falling weight ofthe empty bucket in lowering will not have to be absorbed by anyfrictional clutches, brakes, dynamic energy or by the backing down of asteam engine or similar expedient. My apparatus, when sufficientcounterweight is used, will require positive energy in lowering theempty bucket and lifting the counterweight. It

will require also positive energy for lifting the loaded bucket but onlyabout one-third of that required by the machines in common use, if thebucket be fully counterweighted.

In the simplest form of my invention as illustrated in Fig. 2, Iprovide. suflicient power in the closing motor 20 to cause the bucket todig into the material to be excavated without any auxiliary mechanicaladvantage, and I provide sufficient accelerating means onthe holdingmotor 18 to cause it to overtake the closing motor within a reasonabletime after the latter has closed the bucket and caused it to startupward. In the improved form of my apparatus illustrated in Fig. 3, Iprovide a mechanical advantage to assist the closingmotor in cansing thebucket to dig into the material to be excavated, this mechanical devicebeing automatically turned out of gear as soon as the holding drum haswound in the slack holding rope and overtaken the closing drum.

In the third form of my apparatus which is the only one suited for largemachines, I provide means for permitting the holding drum to revolvewiththe closing drum with sufficient power to prevent any slack in theholding rope but without pulling so hard on the bucket as to materiallydecrease its digging power. In this form I may or may not also provide amechanical device to give the closing motor additional power to closethe bucket which is automatically thrown out of operation when theholding motor is working with the closing motor to lift the bucket.

I do not wish to limit myself, however, to

the particular arrangement or mechanical devices shown 1n these drawingsor described in the above specifications, the arrangements selected forillustration being merely to explain the principle involved.

In the Figs. 2, 3 and' I have indicated solenoid brakes on the motors bythe letter S. It is desirable to have solenoid brakes to hold eithermotor still when the current is cut off as well as to hold it in case offailure of the current. In the case of a reversing steam engine the sameresult would be accomplished by throwing the valve mechanism to theneutral position.

In the foregoing description and in the figures I have shown anddescribed a counterweight as being used in connection with the holdingdrum and as this is of obvious The use of a counterweight, however, isnot an essential part of my apparatus for it is evident that if theclosing motor be made large enough to lift the bucket without thecounterweight there is nothing to prevent doing so, and for lowering theempty bucket without a counterweight, the negative resistance of a motoror a steam engine or even a friction brake could be made use ofas isdone in mostof the machines now in use. It might be, furthermore,advantageous in some instances to omit the counterweight as in the casewhere the horizontal movement of the bucket is considerable whencompared with its vertical movement. In such cases the independentcontrol of the holding and closing drums by separate motors Without acounterweight would not benew and the invention herein described wouldonly apply if some mechanical means such as the planetary gears wereintroduced to assist the closing motor to cause the bucket to dig intothe material which mechanical means were afterward thrown out of actionwhen the holding drum was brought up to speed or this invention would beinvolved in case the holding drum were connected to its driving power insuch a way as to permit it to overrun its driver under the influence ofsome part of the closing mechanism for the purpose ofkeeping the holdingdrum rope tight until the holding motor could be brought up to properspeed.

I claim as my invention,

1. A hoisting mechanism comprising separate holding and closing drums,separately controlled reversible motors for driving the same, and anequalizer gearing connecting other standing, together with acounterweight operatively connected to the holding drum.

3. A hoisting mechanism comprising separate holding and closing drums,separately controlled reversible motors for driving the same, and anequalizer gearing connecting the closing drum with both motors wherebysaid drum may be driven at half speed with full torque by either motorrunning and the other standing, together with a clutch for locking onedrum system to the other.

4. A hoisting mechanism comprising separate holding and closing drums,separately controlled reversible motors for driving the same, and anequalizer gearing connecting the closing drum with both motors wherebysaid drum may be driven at half speed with full torque by either motorrunning and the other standing, together with a clutch for locking onedrum system to the other, and a counterweight operatively connected tothe holding drum.

5. A hoisting mechanism comprising separate drums, a frictional dragdevice between the same, independently-controlled reversible motor meansrespectively geared to said drums, and comprising for one of said drumsa one-way driving mechanism between said drum and its motor, wherebysaid drum may rotate in advance of its motor under the influence of thedrag of the other drum.

6. A hoisting mechanism comprising separate drums, a frictional dragdevice between the same, independently-controlled reversible motor meansrespectively geared to said drums, and comprising for one of said. drumsa one-Way driving mechanism between said drum and its motor, wherebysaid drum may rotate in advance of its motor under the influence of thedrag of-the other drum, together with means for locking said drumsystems together so that the drums revolve in unison.

7. A hoisting mechanism comprising separate drums, a' frictional dragdevice between the same, .independent reversible motor meansrespectively geared to said drums, ratchet and pawl mechanism in one ofsaid gear systems to permit the speed of the drum in said system toexceed that of its motor, in combination with means for locking the drumsystems together so that the drums will revolve in unison.

8. A hoistin mechanism comprising separate drums, a rictional dragdevice between the same, independent reversible motor means respectivelygeared to said drums,

ratchet and pawl mechanism in one of said gear systems to permit thespeed of the drum in said system to exceed that of its motor, togetherwith a counterweight operatively connected to said drum to assist theratchet drive, in combination with means for looking the drum systemstogether so that the drums will revolve in unison.

9. A hoisting mechanism comprising separate winding drums, a frictionaldrag device between the same, separately-controlled reversible motormeans each geared to one of the windin drums, a ratchet and pawlmechanism 1n one said gear systems to permit the speed of the drum insaid system to exceed that of its motor, in combination with amultiplying gear arranged between the respective gear systems butinactive when the drums are running at the same speed, whereby the powerof one drum may be increased at the expense of its speed.

10. A hoisting mechanism comprising sep arate winding drums, africtional drag device between the same, separately controlledreversible motor means each geared to one of the winding drums, aratchet and pawl mechanism in one of said gear systems to permit thespeed of the drum in said system to exceed that of its motor, incombination with a multiplying gear arranged between the respective gearsystems but inactive when the drums are running at the same speed,

whereby the power of one drum may be inv to exceed that of its motor, incombination with a multiplying gear arranged between the respective gearsystem but inactive when the drums are running at the same speed,whereby the power of one drum may be increased at the expense of itsspeed, together with a counterweight operatively connected to theratchet controlled drum, and opposed tothe weight to be lifted thereby,and means for locking one drum system to the other.

In testimony whereof I have signed my name to this specification, in thepresence of two subscribing witnesses.

AUGUSTUS SMITH.

Witnesses:

WALTER Anna, L. Gnorn.

